Electrodeposition of nickel



Patented Aug. 13, 1940 UNITED STATES PATENT OFFICE,

2,211,535 nrnc'rnonnrosrrron O-F NICKEL Henry Brown, Detroit, Mich assignor, by mesne assignments, to The Udylite Corporation, a corporation of Delaware No Drawing. Application June 13, 1938, Serial No. 213,454

Claims. (01. 204-14) Table I with their optimum concentration in.

baths prepared from nickel sulphate, nickel J produces a degree of grain refinement and brightchloride and boric acid and containing 75 g./1. Ni, 15 g./l. chloride and 35 g./l. boric acid. The temperature of the plating solution can range from room temperature to boiling and preferably from. room temperature to 55 0., ordinarily 50 C. The pH of the solution may vary between 1.5 and 3.5 and preferably 2.03.0. The preferred current densities range between 4.0 and 7.5

amp/sq. dm,

The presence of other inorganic salts such as NH; and Na salts does not interfere with the beneficial action of these organic compounds as long as inorganic materials are present in such amounts which are common in ordinary white nickel baths. Thus the invention is not limited to any specific nickel'plating bath.

319 Table I Grams per liter Phenyl arsonic acid, c6H5.Aso(oH)z 1.0 an

Benzylarsonic acid, CsH5.CHz.AsO(OH) 2 1.0 -2.0 n-Butyl arsonic acid, C3H'1.ASO(OH)2 1.0 -2.0

5 Allyl arsonic acid,

CI-I2=CH.CH2.A5O(OH)2.. .75-15 Lower concentrations than those given in Table I have found that the addition of relatively small amounts of arsonic acids, for example, .5 g./l. phenyl arsonic acid to a nickel bath which also contains a sulphonamide (see my copending 55 application Serial No. 162,696, filed September 7,

1937) for example, 2 g./l. o-toluene sulphonam-- ide, or to a bathcontaining a suitable substituted phenyl sulphonic acid, for example, 2 g./1. thymol sulphonic acid or 2 g. /l. dichlorobenzene sulphonic acid (see my copending application Serial No. 5 213,456, filed June 13, 1938), or a' naphthalene sulphonic acid such as 2 g./1. naphthalene disulphonic acid (see United States Patent No. 905,837

to Broadwell) or an alkyl substituted naphthalene sulphonic acid such as 2 g./1, di-isopropyl m naphthalene sulphonic acid (see United States Patent No. 1,818,229 to Lutz and Westbrook),

ness whichcannot be obtained with these compounds alone, especially at high current densiw ties. To get the most desirable effect the pH should be kept low, between 2 and 3.

\ I havealso found that the addition of small amounts of auxiliary brighteners which plate out with the nickel such as zinc and cadmium in an the form of, for example, chlorides or sulphates, and. selenium and tellurium in the, form of, for example, their oxides or acids, increase greatly the degree of brightness obtained with the arsonic acids. This combination can be used 25;

where high ductility and maximum corrosion resistance are non-important. The optimum concentrations of these auxiliary brighteners are given in Table II.

'Table II 3a Grams per liter Zinc .25 Cadmium A .115 Tellurium .15

I claim:

1. The method .of electrodepositing nickel which comprises electrolyzing an aqueous acid solution comprising essentially a substance selected from the group consisting of nickel sulphate, nickel chloride, and nickel. sulphate and nickel chloride together in the presence of an arsonic acid. I

2. The method of electrodepositing nickel '4. The method of electrodepositing nick which comprises electrolyzing an' aqueous acid solution comprising essentially nickel sulphate, nickel chloride and boric acid in the presence 0! an arsonic acid in an amount not exceeding approximately 2 grams per liter.

5; A nickel plating bath comprising an aqueous acid solution comprising essentially a substance selected from the group consisting of nickel sulphate, nickel chloride, and nickel sulphate and nickel chloride together, and an arsonic acid. 6. A nickel plating bath comprising an aqueous acid solution comprising essentially nickel sulphate, nickel chloride and boric acid, and an arsonic acid.

7. A nickel plating bath comprising an aqueous acid solution having a pH falling within a range of from 1.5 to 3.5 and comprising essentially a substance selected from the group consisting of nickel sulphate, nickel chloride, and nickel sulphate and nickel chloride together and an arsonicacid.

- nickel. chloride together, an arsonic acid and a small amount of a metal from the group consisting of zinc, cadmium, selenium and tellurium.

10. The method of electrodepositing nickel which comprises electrolyzing an aqueous acid solution comprising essentially nickel sulphates, nickel chloride and boric acid, and phenyl arsonic acid.

HENRY BROWN. 

